tachi (weapon)
A tachi (太刀) was a type of traditionally made Japanese sword (nihonto) worn by the samurai class of feudal Japan. The tachi style of swords preceded the development of the katana — the first use of the word katana to indicate a blade different from tachi appears toward the end of the twelfth century.
Chokutou, straight swords, were also called tachi, but written as 大刀.